In smaller sized greenhouses, a manual system opened and closed by hand could be installed. These work easiest when the screen material is supported by a track system.
Start time – when each morning will the screen system start operation
Stop time – when in the afternoon will the display system stop operation
Light level – in what light intensity will the screen be activated either to open or close
Maximum/minimum temperature – what are the limitations of temperature desired
Maximum/minimum humidity – What are the limitations of humidity desired
Gap positions – this pieces the percent open or close position under different circumstances such as in early stages a winter early morning to lessen thermal shock or through the summer to supply better shading. The gap measures and speed of movement can be controlled in a few systems.
Time delay – under changeable weather conditions this avoids frequent opening and closing
Wind speed – To lessen temperature loss, the screen could be closed early below high wind speed conditions
Snow detection – this can open the display and turn on the heat when it 
begins to snow.
The typical system uses nylon monofilament or stainless cables to support the screen materials. The screen material can possibly rest along with the network of cables or be suspended by hooks from the cables. A gearmotor Rack Drive For Greenhouse powers a drum or rack and pinion that techniques the industry leading of the screen materials. Control is usually either with a manual change or electronic controller.
Based on the over, the grower must enter the next parameters into the controller:
A weather station is needed to provide outdoor light level, temperature, humidity, wind and rain or snow conditions.